Pressure swirl flow injector with reduced flow variability and return flow

ABSTRACT

A reagent injector with a cartridge design has a body with a reagent inlet, outlet, and a swirl chamber, which has an exit orifice that may be covered and uncovered by a solid, movable pintle. Reagent flows through the injector when the exit orifice is covered and uncovered to cool the injector. An insulator may be disposed between the injector body and a mounting flange connectable to an exhaust system. A flow path ensures cooling of an electromagnetic actuator. Reagent may bypass an orifice swirl chamber when the pintle blocks the exit orifice. Fluid may flow between an outside diameter of a pole piece and an inside diameter of an electromagnetic actuator, through an orifice chamber and return through a central bore housing a solid pintle, around which fluid may flow. Different inner injector body passages may direct fluid into an orifice distribution chamber and out to the solid pintle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/303,146, filed on Feb. 10, 2010. The entire disclosure of the aboveapplication is incorporated herein by reference.

FIELD

The present disclosure relates to injector systems and, moreparticularly, relates to an injector system for injecting reagent, suchas an aqueous urea solution, into an exhaust stream to reduce oxides ofnitrogen (NOx) emissions from diesel engine exhaust.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art. Lean burn engines provideimproved fuel efficiency by operating with an excess of oxygen, that is,a quantity of oxygen that is greater than the amount necessary forcomplete combustion of the available fuel. Such engines are said to run“lean” or on a “lean mixture.” However, this improved or increase infuel economy, as opposed to non-lean burn combustion, is offset byundesired pollution emissions, specifically in the form of oxides ofnitrogen (NOx).

One method used to reduce NOx emissions from lean burn internalcombustion engines is known as selective catalytic reduction (SCR). SCR,when used, for example, to reduce NOx emissions from a diesel engine,involves injecting an atomized reagent into the exhaust stream of theengine in relation to one or more selected engine operationalparameters, such as exhaust gas temperature, engine rpm or engine loadas measured by engine fuel flow, turbo boost pressure or exhaust NOxmass flow. The reagent/exhaust gas mixture is passed through a reactorcontaining a catalyst, such as, for example, activated carbon, ormetals, such as platinum, vanadium or tungsten, which are capable ofreducing the NOx concentration in the presence of the reagent.

An aqueous urea solution is known to be an effective reagent in SCRsystems for diesel engines. However, use of such an aqueous ureasolution involves many disadvantages. Urea is highly corrosive and mayadversely affect mechanical components of the SCR system, such as theinjectors used to inject the urea mixture into the exhaust gas stream.Urea also may solidify upon prolonged exposure to high temperatures,such as temperatures encountered in diesel exhaust systems. Solidifiedurea will accumulate in the narrow passageways and exit orifice openingstypically found in injectors. Solidified urea may also cause fouling ofmoving parts of the injector and clog any openings or urea flowpassageways, thereby rendering the injector unusable.

In addition, if the urea mixture is not finely atomized, urea depositswill form in the catalytic reactor, inhibiting the action of thecatalyst and thereby reducing the SCR system effectiveness. Highinjection pressures are one way of minimizing the problem ofinsufficient atomization of the urea mixture. However, high injectionpressures often result in over-penetration of the injector spray plumeinto the exhaust stream, causing the plume to impinge on the innersurface of the exhaust pipe opposite the injector. Over-penetration alsoleads to inefficient use of the urea mixture and reduces the range overwhich the vehicle can operate with reduced NOx emissions. Only a finiteamount of aqueous urea can be carried on a vehicle, and what is carriedshould be used efficiently to maximize vehicle range and reduce the needfor frequent replenishment of the reagent.

Further, aqueous urea is a poor lubricant. This characteristic adverselyaffects moving parts within the injector and requires that relativelytight or small fits, clearances and tolerances be employed betweenadjacent or relatively moving parts within an injector. Aqueous ureaalso has a high propensity for leakage. This characteristic adverselyaffects mating surfaces requiring enhanced sealing resources in manylocations.

It would be advantageous to provide methods and apparatus for injectingan aqueous urea solution into the exhaust stream of a lean burn enginesuch that heat and operational consistency can be more reliably managed.It would be further advantageous to provide improved cooling and/or heatmanagement of the injector to prevent the urea from solidifying and toprolong the life of the injector components. It would be advantageous tominimize heat transfer to the injector from the exhaust pipe to minimizeor eliminate urea deposit formation internal to the injector. It wouldalso be advantageous to minimize heat transfer from the hot exhaust gasto the injector exit orifice to prevent soot and urea from beingattracted to the relatively cool injector exit orifice. It would also beadvantageous to provide an injector that does not leak for economicaland environmental purposes.

Methods and apparatus of the present disclosure provide the foregoingand other advantages.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

In some embodiments, a method of directing reagent through an injectormay involve: receiving a reagent from a reagent tank at a reagent inletof a reagent injector; directing the reagent to a pole piece passagedefined between an outside diameter of a pole piece and an insidediameter of an electromagnetic bobbin; directing the reagent from thepole piece passage to a collar passage defined between an outsidediameter of a collar of an inner lower body and the inside diameter ofthe bobbin; directing the reagent from the collar passage to a lowerbody passage defined between an outside diameter of the inner lower bodyand an inside diameter of a lower section of the injector; and directingthe reagent into a distribution passage defined by the inner lower body.The distribution passage may fluidly link the lower body passage to adistribution chamber defined by the inner lower body and an orificeplate. In some embodiments, from the distribution chamber, the methodmay include directing a first partial volume of the reagent to anorifice in the orifice plate and directing a second partial volume ofthe reagent to a reagent outlet of the injector.

In some embodiments, directing a first partial volume of the reagent toan orifice in the orifice plate may include: directing the first partialvolume of the reagent through a plurality of slots in the orifice plate;moving a pintle and unblocking the orifice in the orifice plate;directing the first partial volume of the reagent through a plurality ofslots in the orifice plate and through the orifice; and directing thefirst partial volume of the reagent to a central bore defined by theinner lower body.

In some embodiments, directing a second partial volume of the reagent toa reagent outlet may include: directing the second partial volume of thereagent through holes defined in a guide plate through which a pintlepasses; directing the second partial volume of the reagent through holesof a pintle head, the pintle head attaching to and surrounding an end ofthe pintle; directing the second partial volume of the reagent throughan interior of a bobbin of a magnetic coil; directing the second partialvolume of the reagent through a central bore of a pole piece; directingthe second partial volume of the reagent from the distribution chamberto at least one return passage defined by the inner lower body, whereinthe return passage fluidly links the distribution chamber and a centralbore defined by the inner lower body. Directing the second partialvolume of the reagent around an outside diameter of a solid pintleresiding within a central bore defined by the inner lower body.

In some embodiments, an injector for injecting reagent may employ anupper injector body, a lower injector body that may be secured to theupper injector body, a retaining plate defining a circular hole suchthat the retaining plate may be secured around the lower injector bodyvia the circular hole, an insulator defining a circular hole such thatthe insulator may be secured around the lower injector body, and amounting flange defining a circular hole such that the mounting flangemay be secured around the insulator. The retaining plate may be secureddirectly against the lower injector body. The insulator may be secureddirectly against the lower injector body and the retaining plate. Themounting flange may be secured directly against the insulator. Theretaining plate may define a plurality of through holes about aretaining plate peripheral edge and the mounting flange may define aplurality of blind holes about a mounting flange peripheral edge. A pinhaving a first pin end and a second pin end may be employed such thatthe first pin end resides within one of the blind holes of the mountingflange and the pin resides completely through one of the plurality ofthrough holes of the retaining plate.

In some embodiments, a clip having a first clip end and a second clipend may be utilized in such a fashion that the clip may be secured overthe retaining plate peripheral edge and the mounting flange peripheraledge. The retaining plate peripheral edge may define a peripheralconcavity and the plurality of through holes of the retaining plate maybe located within the peripheral concavity. The mounting flangeperipheral edge may define a groove. The first clip end may residewithin the groove of the mounting flange peripheral edge and the secondclip end may reside within the peripheral concavity of the retainingplate peripheral edge. The clip may be C-shaped and the second clip endmay reside on the second pin end. The insulator may define a tubularsection with an inside diameter and an outside diameter that each have aseries of alternating protrusions and recessions.

In some embodiments, a heat shield may be installed on the mountingflange using a through in the heat shield such that the mounting flangemay protrude through the through hole of the heat shield. In someembodiments, the heat shield may be positioned between an injector upperbody and an exhaust pipe. A cover may be mounted to the heat shield suchthat the cover surrounds the upper injector body, the lower injectorbody, and the mounting flange.

In some embodiments, an injector for injecting reagent may employ acylindrical pole piece defining a pole piece first end and a pole piecesecond end. The pole piece may have a hollow interior from the polepiece first end to the pole piece second end. A spring pre-loader may belocated within the hollow interior and against a portion of the firstend. A spring may be located within the hollow interior and abut thespring pre-loader. An electromagnetic coil may be secured around abobbin and the electromagnetic coil may itself surround an outsidediameter of the cylindrical pole piece. In some embodiments, thecylindrical pole piece, spring pre-loader, spring and electromagneticcoil reside only within a cavity or chamber of the upper injector body.

A cylindrical inner lower body may reside within a lower injector bodyand define a longitudinal central bore. An inner lower body first endmay define a first end first bore with a diameter larger than a diameterof the longitudinal central bore. The inner lower body first end mayalso define a first end second bore with a diameter larger than thelongitudinal central bore and larger than the first end first bore. Aninner lower body second end may define a second end bore with a diameterlarger than the longitudinal central bore. The injector may furtheremploy a solid pintle residing within the longitudinal central bore. Aguide plate may be attached to an intermediate portion of the pintle.The guide plate may reside within the first end first bore. A pintlehead may surround an end of the pintle of part of the end of the pintle.The pintle head may reside within the first end second bore; and anorifice plate residing within the second end bore. The cylindrical polepiece, spring pre-loader, spring, electromagnetic coil, cylindricalinner lower body, pintle, guide plate, pintle head and orifice plate maybe part of a single cartridge.

In some embodiments, an injector body upper section may define a chamberwithin which the single cartridge, or part of the single cartridge, mayinsert into and reside. The guide plate may define one or more throughholes for passage of fluid. Alternatively, the guide plate and thepintle together may define one or more through holes therebetween forpassage of fluid. The pintle head may define at least one through holefor passage of fluid. The orifice plate and the inner lower body secondend may define a distribution chamber therebetween. The orifice platemay define a plurality of grooves for passage of fluid to an exitorifice for exit from the injector. An interior surface of the injectorbody lower section and an inner lower body exterior surface may define afluid pathway. The inner lower body may define a distribution passagefluidly linked to the pathway defined by an interior surface of theinjector body lower section and an exterior surface of the inner lowerbody. The inner lower body may define a return passage that fluidlylinks the inner lower body central bore and the distribution chamberdefined by the orifice plate and the inner lower body second end. Thesolid pintle may reside within the longitudinal central bore for passageof fluid around the solid pintle and through the longitudinal centralbore.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 depicts a schematic diagram of an exemplary on-road diesel enginewith a pollution emission control system using an injector according tothe present teachings;

FIG. 2A depicts an exploded view of a reagent injector according to someembodiments of the present teachings;

FIG. 2B depicts an exploded cross-sectional view of the reagent injectorof FIG. 2A according some embodiments of the present teachings;

FIG. 3A depicts a cross-sectional view of the reagent injector;

FIG. 3B depicts another cross-sectional view of the reagent injector;

FIG. 4 depicts a bottom perspective view of the reagent injector mountedin an exhaust system;

FIG. 5 depicts a top perspective view of the reagent injector mounted inan exhaust system;

FIG. 6 depicts a top perspective view of a reagent injector according tosome embodiments of the present teachings;

FIG. 7 depicts a top perspective view of a reagent injector according tosome embodiments of the present teachings;

FIG. 8 depicts a top perspective view of a reagent injector according tosome embodiments of the present teachings;

FIG. 9 depicts a top perspective view of an insulator and mountingflange of an injector mount according to the present teachings;

FIG. 10 depicts an exploded view of an insulator and mounting flange ofan injector mount according to the present teachings;

FIG. 11 depicts a cross-sectional view of the insulator and mountingflange of FIGS. 9 and 10 according to the present teachings;

FIG. 12 depicts an exploded view of a pintle and plunger according tothe present teachings;

FIG. 13 depicts a cross-sectional view of the pintle and plungeraccording to the present teachings;

FIG. 14 depicts a side view of a lower injector body and pintleaccording to the present teachings;

FIG. 15 depicts an exploded view of the lower injector body and pintleaccording to the present teachings;

FIG. 16 depicts a perspective view of an orifice plate according to thepresent teachings;

FIG. 17 depicts a perspective view of a guide member according to thepresent teachings;

FIG. 18 depicts a cross-sectional view of the lower injector body andpintle according to the present teachings;

FIG. 19 depicts a top perspective view of a pole piece and inner lowerbody according to the present teachings;

FIG. 20 depicts an exploded view of the pole piece and inner lower bodyaccording to the present teachings;

FIG. 21 depicts a cross-sectional view of the pole piece and inner lowerbody according to the present teachings;

FIG. 22 depicts a top perspective view of the lower section of theinjector body and retaining plate according to the present teachings;

FIG. 23 depicts an exploded view of the lower section of the injectorbody and retaining plate according to the present teachings;

FIG. 24 depicts a cross-sectional view of the lower section of theinjector body and retaining plate according to the present teachings;

FIG. 25 depicts a top perspective view of the lower section of theinjector body and inner lower body according to the present teachings;

FIG. 26 depicts an exploded view of the lower section of the injectorbody and inner lower body according to the present teachings;

FIG. 27 depicts a cross-sectional view of the lower section of theinjector body and inner lower body according to the present teachings;

FIG. 28 depicts a top perspective view of the magnetic coil assemblyaccording to the present teachings;

FIG. 29 depicts an exploded view of the magnetic coil assembly accordingto the present teachings;

FIG. 30 depicts a cross-sectional view of the magnetic coil assemblyaccording to the present teachings;

FIG. 31 depicts a top perspective view of the bobbin assembly accordingto the present teachings;

FIG. 32 depicts an exploded view of the bobbin assembly according to thepresent teachings;

FIG. 33 depicts a cross-sectional view of the bobbin assembly accordingto the present teachings;

FIG. 34 depicts a top perspective view of the fluid coupling assemblyaccording to the present teachings;

FIG. 35 depicts an exploded view of the fluid coupling assemblyaccording to the present teachings;

FIG. 36 depicts a cross-sectional view of the fluid coupling assemblyaccording to the present teachings;

FIG. 37 depicts a top perspective view of the partial reagent injectoraccording to the present teachings;

FIG. 38 depicts an exploded view of the partial reagent injectoraccording to the present teachings;

FIG. 39 depicts a cross-sectional view of the partial reagent injectoraccording to the present teachings;

FIG. 40 depicts a top perspective view of the reagent injector accordingto the present teachings;

FIG. 41 depicts an exploded view of the reagent injector according tothe present teachings;

FIG. 42 depicts a cross-sectional view of the reagent injector accordingto the present teachings;

FIG. 43 depicts a top perspective view of the reagent injectorincorporated into an exhaust system according to the present teachings;

FIG. 44 depicts a side view of the reagent injector incorporated into anexhaust system according to the present teachings;

FIG. 45 depicts a top view of the reagent injector incorporated into anexhaust system according to the present teachings;

FIG. 46 is a graph showing a conventional control signal;

FIG. 47 is a graph showing a peak and hold control signal according tothe present teachings; and

FIG. 48 is a cross-sectional view of the reagent injector depictingfluid flow paths through the injector according to the presentteachings.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference toFIGS. 1-48 of the accompanying drawings. It should be understood thatalthough the present teachings may be described in connection withdiesel engines and the reduction of NOx emissions, the present teachingscan be used in connection with any one of a number of exhaust streams,such as, by way of non-limiting examples, those from diesel, gasoline,turbine, fuel cell, jet or any other power source outputting a dischargestream. Moreover, the present teachings can be used in connection withthe reduction of any one of a number of undesired emissions. Foradditional description, attention should be directed tocommonly-assigned U.S. patent application Ser. No. 12/275,539, filedNov. 21, 2008, entitled “Method And Apparatus For Injecting AtomizedFluids”, which is incorporated herein by reference. Thus, the presentinvention provides improved methods and apparatus structure forinjecting a reagent, such as an aqueous urea solution, into an exhauststream in order to reduce emissions from engine exhaust. Moreover, thepresent teachings provide improvements to prior art aqueous ureainjectors, in particular, improvements to an aqueous urea injectorincluding improved heat dissipation of critical components, reduced sizeand complexity of the reagent injector, and improved operation andfunction.

FIG. 1 depicts an example pollution control system for reducing NOxemissions from the exhaust of a diesel engine 10. In FIG. 1, solid linesbetween elements of the system denote fluid lines for reagent and dashedlines denote electrical connections. The system of the present teachingsmay include a reagent tank 12 for holding the reagent and a deliverymodule 14, such as a pump, for delivering the reagent from the reagenttank 12. The reagent may be a urea solution, a hydrocarbon, an alkylester, alcohol, an organic compound, E-85, water, or the like and can bea blend or combination thereof. It should also be appreciated that oneor more reagents can be available in the system and can be used singlyor in combination. Reagent tank 12 and delivery module 14 may form anintegrated reagent tank/delivery module. Also provided as part of thesystem is an electronic injection controller 16, a reagent injector 100,which may be a low pressure reagent injector, and an exhaust system 18having at least one catalyst bed 20.

Delivery module 14 may comprise a pump that supplies reagent fromreagent tank 12 through an in-line filter 22 via a supply line 24.Reagent tank 12 may be polypropylene, epoxy coated carbon steel, PVC, orstainless steel and sized according to the application (e.g., vehiclesize, intended use of the vehicle, and the like). Filter 22 may includea housing constructed of rigid plastic or stainless steel with aremovable filter cartridge. A pressure regulator (not shown) may beprovided to maintain the system at a predetermined pressure set point(e.g., relatively low pressures of approximately 60-80 psi, or in someembodiments a pressure of approximately 60-150 psi) and may be locatedin return line 26 from reagent injector 100. A pressure sensor may beprovided in the flexible supply line 24 leading to the reagent injector100. The system may also incorporate various freeze protectionstrategies to thaw frozen urea or to prevent the urea from freezing. Forexample, during system operation, regardless of whether or not theinjector is releasing reagent into the exhaust gases, such as in anengine exhaust pipe, reagent is circulated continuously between (i.e.from and to) reagent tank 12 and reagent injector 100 to cool theinjector and minimize the dwell time of the reagent in the injector sothat the reagent remains cool.

Continuous reagent circulation may be necessary fortemperature-sensitive reagents, such as aqueous urea, which tend tosolidify upon exposure to elevated temperatures of 300° C. to 650° C. asmay be experienced in an engine exhaust system. It has been found to beimportant to keep a given urea mixture or solution below 140° C. andpreferably in a lower operating range between 5° C. and 95° C. toprovide a margin of safety ensuring that solidification of the urea isprevented. Solidified urea, if allowed to form, may foul moving parts,openings and passageways of the injector, possibly rendering theinjector useless for its intended purpose. It will be recognized thatflow rates will depend on engine size and NOx levels.

The amount of reagent required may vary with load, engine RPM, enginespeed, exhaust gas temperature, exhaust gas flow, engine fuel injectiontiming, and desired NOx reduction. All or some of the engine operatingparameters may be supplied from engine control unit 28 via theengine/vehicle databus to reagent electronic injection controller 16.Reagent electronic injection controller 16 may also be included as partof engine control unit 28 if a given engine, vehicle or truckmanufacturer agrees to provide such functionality. Exhaust gastemperature, exhaust gas flow and exhaust back pressure may be measuredby respective sensors.

With reference now including FIGS. 2A and 2B, an exemplary embodimentand variations of reagent injector 100 will be further described. In itsexemplary use in the system depicted in FIG. 1, reagent injector 100 mayhave an injector body 102 having an injector body upper section 102 aand an injector body lower section 102 b. An elongated inner lower body104 may be received within at least one of injector body upper section102 a and injector body lower section 102 b. Elongated inner lower body104 may define a cylindrical central bore 106, which may be in fluidcommunication with an orifice plate 108, which may define at least oneexit orifice 110 (FIG. 16) that passes completely through the orificeplate 108. Inner lower body 104 may or may not be equipped with aseparate guide plate 107 (FIG. 18). As depicted in FIGS. 2B, 3A and 3B,inner lower body 104 may be tapered at an end portion adjacent a pintlehead of pintle 118. More specifically, instead of a separate guide plateto guide or maintain alignment of pintle 118 within a consistent centralbore 106 (FIG. 3B), inner lower body 104 may be tapered or have astep-down in bore that has a smaller inner diameter than central bore106. As depicted in FIGS. 2B, 3A and 3B, this step-down in bore at endof inner lower body 104 adjacent a pintle head, may be a guide memberfor pintle 118 and attached pintle head. Moreover, a pintle head ofpintle 118 may act as a guide member to ensure that pintle head, whichalso may be referred to as a plunger, moves back and forthlongitudinally within central bore 106.

Numerous orifices through orifice plate 108 are possible to permit fluidflow through orifice plate and into an exhaust gas stream within anexhaust pipe of the exhaust system 18 (FIGS. 1, 4, 5, and 43-45) of adiesel engine when injector 100 is mounted to the exhaust pipe.Depending upon application and operating environment, orifice plate 108may be made of a carbide material, which may provide desired performancecharacteristics and may be more easily and cost-effectivelymanufactured. Moreover, limitations or disadvantages associated withother materials and manufacturing processes may be avoided, such asthose associated with manufacturing complex part shapes. Carbide mayprovide additional advantages, such as insensitivity to brazingtemperatures (870-980° C.), as opposed to other steels, such as carbonsteels and tools steels, which may distemper. Carbide may also permitthe hardness of surfaces of parts to be much greater than thatachievable with most or all steels. As an example, using Mohs scale ofmineral hardness, diamond may have a hardness of 10, carbide may have ahardness of 9-9.5 and hardened steel may be in the range of is 4-6.Thus, carbide is advantageous with regard to overall wear resistance.Moreover, carbide also has a wide range of toughness and can be “finetuned” to have the best properties for a particular application.

Orifice plate 108 may be coupled to and retained by the elongated innerlower body 104 using an orifice plate holder 112. Orifice plate holder112 may be integrally formed with inner lower body 104, if desired, asdepicted in FIGS. 14, 15, and 18. In some embodiments, if orifice plateholder 112 is formed separately, orifice plate holder 112 may include acentral male portion 114 (FIG. 2B) sized to be received and retainedwithin a corresponding female portion 116 of elongated inner lower body104. Surrounding exit orifice 110 may be a valve seat 120 (FIGS. 16 and18), which may be conical or cone-shaped, or any practical shape;however, a conical shape is preferred as shown, for example, in FIG. 16.A valve member in the form of an elongated metering plug or pintle 118(FIGS. 2A, 2B, 12, 13, 15, and 18) may be slidably mounted withincentral bore 106 and engagable with valve seat 120 to define a sealedand closed position when seated, and an unsealed and opened positionwhen unseated. In some embodiments, orifice plate 108 may be coupled toinner lower body 104 via a press fit connection, which may then undergobrazing.

Referring to FIGS. 2A, 2B, and 19-21, reagent injector 100 may employ anelongated pole piece 122 having an enlarged diameter end portion 124sized to be received within a correspondingly sized collar portion 126of elongated inner lower body 104. In some embodiments, elongated polepiece 122 may be press fit into inner lower body 104. Upon installation,the connection or press fit parts may also or alternatively be electronbeam welded. A flange 128 of pole piece 122 can be sized to limit theengagement depth of pole piece 122 within elongated inner lower body 104to define a space 130 therebetween (FIG. 21). Space 130 can be sized toreceive a pintle head 132 (FIGS. 12, 13, and 21) of pintle 118 andpermit limited and controlled axial movement of pintle 118 withincentral bore 106. In some embodiments, pintle head 132 may be attachedto a shaft of pintle 118 via a press fit and/or furnace braze. Pintlehead 132, which also may be referred to as a pintle head, may includethrough holes formed therein to reduce hydraulic pressure and provide areturn flow path for fluid passage. Guide plate 107 (FIGS. 14, 15, 17and 18), which may also be referred to as a guide member, may supportpintle 118 to provide guided movement of pintle 118 in central bore 106.Guide plate 107 may comprise a plurality of slots or holes 109 to permitfluid flow therethrough. That is, guide plate 107 may define one or moreslots or holes 109 that are through slots to permit fluid to flowthrough, even when pintle 118 is attached to guide plate 107.

As depicted in FIGS. 2A, 2B, 20, and 21, elongated pole piece 122 mayfurther define a central bore 134 extending therethrough about a centralaxis of elongated pole piece 122. Central bore 134 may receive a returnspring 136 and a spring pre-loader 138. Spring pre-loader 138 may besized and/or shaped to engage and preload return spring 136. Morespecifically, spring pre-loader 138 may contact a structure formedwithin central bore 134 of pole piece 122 to prevent movement thereinand serve to limit the space available for extension of return spring136. Spring pre-loader 138 may be retained in any one of a number ofconventional ways, including using obstructions or features formed incentral bore 134 that prevent passage of spring pre-loader 138.Alternatively, adjustable mechanisms, such as retaining screws, may beused to limit or adjust the position of spring pre-loader 138. In thisway, return spring 136 is permitted to exert a biasing force upon pintlehead 132 of pintle 118, thus urging an end of pintle 118 into engagementwith valve seat 120 and thus closing or preventing fluid flow throughorifice plate 108. Return spring 136 and spring pre-loader 138 comprisea central bore that is hollow and permits fluid flow through a centralportion of return spring 136 and a central portion through pre-loader138.

FIGS. 6-8 depict injectors 101 with various configurations orarrangements of fluid inlets and fluid outlets that may protrude frominjector body upper sections 102 a. Moreover, injector body uppersection 102 a may be formed or molded from a single material, and as asingle piece as opposed to two pieces, such that a fluid inlet, a fluidoutlet, and an electrical connector housing may all be molded in asingle piece as a portion of injector body upper section 102 a. Such aconstruction facilitates insertion of a cartridge of componentspre-assembled as a cartridge, as depicted in FIG. 21, which will bediscussed later. FIGS. 4-6 also depict an injector mount to facilitatemounting of injectors 101 to an exhaust component. FIGS. 34-36 also eachdepict an injector 101. FIG. 34 depicts injector 101 without a mount andwith example positions of a fluid inlet 168, a fluid outlet 170 andelectrical connector housing 174. FIG. 35 depicts injector 101 with aninlet port filter 175 and an outlet port filter 177 removed from inlet168 and outlet 170, respectively. FIG. 35 also depicts a flux frame 178of an encapsulated electromagnetic coil and an associated bobbin, allremoved state from injector body upper section 102 a. FIG. 36 is across-sectional view depicting inlet filter 175 installed within inlet168, outlet filter 177 installed within outlet 170, and electromagneticcoil and an associated bobbin surrounded by flux frame 178 installedwithin injector body upper section 102 a.

During assembly (FIGS. 9-42), spring pre-loader 138 and return spring136 may be disposed within central bore 134 of pole piece 122. Endportion 124 of pole piece 122 may be received within collar portion 126of inner lower body 104 and thereby capturing pintle head 132 of pintle118 therebetween such that pintle 118 extends along and within centralbore 106 of inner lower body 104. Longitudinal central axis of pintle118 may be coincident with a longitudinal central axis of central bore106. Male portion 114 of orifice plate holder 112 may be joined orinserted within female portion 116 of inner lower body 104. Femaleportion 116 may be described as a cavity or bore. Injector body uppersection 102 a of injector body 102 may be joined with injector bodylower section 102 b of injector body 102 such that orifice plate holder112, inner lower body 104, pintle 118, pole piece 122, return spring 136and spring pre-loader 138 are captured within a chamber 140 of injectorbody upper section 102 a, and in some embodiments, a chamber 142 ofinjector body lower section 102 b.

With reference to FIGS. 2A, 2B, and 28-33, a disc-shaped bobbin 144which by way of non-limiting example, may be made of Delrin orPolyoxymethylene (commonly referred to as POM and also known aspolyacetal or polyformaldehyde). POM is a thermoplastic that may be usedin manufacturing precision parts that require high stiffness andexcellent dimensional integrity. Continuing, bobbin 144 may have acentral bore 146 and may be positioned and captured between injectorbody upper section 102 a and injector body lower section 102 b such thatinner lower body 104 and pole piece 122 are received within central bore146 of bobbin 144. Specifically, bobbin 144 can be received withincorrespondingly-sized depressions 148, 150 (FIGS. 2A, 2B, and 22-24)formed in injector body upper section 102 a and injector body lowersection 102 b, respectively of injector body 102. In some embodiments,injector body lower section 102 b may comprise a lip 152 that can berolled or formed over a shoulder 154 of injector body upper section 102a to retain injector body lower section 102 b with injector body uppersection 102 a (FIGS. 2A-5). In some embodiments, a seal member, such asan O-ring, can be provided within a seal depression 156 (FIG. 2B)defined within injector body upper section 102 a so that the O-ring issituated between injector body upper section 102 a and injector bodylower section 102 b to define and ensure a leak-proof fluid seal.

To affect the opening and closing of exit orifice 110, an actuator maybe provided, for example in the form of magnetic coil 180 (FIGS. 28-30)mounted in injector body 102 and, in some embodiments, mounted and/orformed with bobbin 144. Magnetic coil 180 of the present teachings ofthe disclosure is substantially smaller compared to traditional coilsused in reagent injectors. This smaller size provides several advantagesover conventional coils, including less heat being generated duringactuation that would otherwise need to be managed through activecooling, such as exterior air cooling, of the reagent injector. Thus,through the use of a smaller magnetic coil in the present disclosure,less heat is generated during coil operation and, consequently, lessactive cooling of the reagent injector is required. By way ofnon-limiting example, it has been found that magnetic coils having 100turns of #29 magnet wire with a 10 mm ID and 17 mm OD and 3.8 mm axiallength is sufficient to reliably actuate reagent injector 100.

When magnetic coil 180 is energized via electrical leads 182 (FIGS. 28and 29), metering pintle 118 is drawn upward from the closed position tothe open position. Upward is a direction that is away from an exhaustpipe to which injector 100 may be mounted. Some members of the assembly,such as enlarged diameter end portion 124 of elongated pole piece 122and pintle head 132, can be made of a magnetic material, such as 430stainless steel, to help promote establishment of a magnetic field.Likewise, some members of the assembly, such as collar portion 126 ofelongated inner lower body 104, may be made of a non-magnetic materialto limit the effect on the metering pintle 118. Magnetic coil 180 may beenergized, for example, in response to a signal from electronicinjection controller 16 of FIG. 1, which decides based upon sensor inputsignals and its preprogrammed algorithms, when reagent is needed foreffective selective catalytic reduction of NOx emissions in the exhauststream within exhaust pipe to which injector 100 is mounted. Tofacilitate movement of pintle 118, pintle head 132 may be aligned with aflux frame of electromagnetic coil 180. For instance, as depicted in atleast FIG. 42, flux frame, which surrounds bobbin 144 andelectromagnetic coil 180, may align with pintle head 132. Thus, incross-sectional view of FIG. 42, if a straight line is drawn betweencross-sectional halves of flux frame, so as to connect flux frame, thestraight line would be drawn through pintle head 132. Such arrangementenhances the electromagnetic effect of electromagnetic coil 180 onpintle head 132.

In some embodiments, electrical leads 182 provide a control signal tothe reagent injector 100, for example from the reagent electronicinjection controller 16 (FIG. 1). Magnetic coil 180 may be energized bya 12-24 VDC current using a pulse width modulated digital signal. Insome embodiments, the control signal may be a simple square wave.However, in some embodiments, it has been found that substantiallyimproved performance and metering of reagent may be achieved through useof a control signal generally similar to that illustrated in FIG. 47.For comparison, with reference to FIG. 46, a conventional square wave isdepicted having a starting impulse (a) at t=0 to a constant output (b)and terminating (c) to zero at t=1. This conventional square waveenergizes a coil and produces a delayed response in an injector—that is,the injector initially opens according to a curved response (d) to afully opened position and finally closes according to a delayed response(e).

According to teachings of the present disclosure, a control signal isprovided in FIG. 47 having a starting impulse (f) at t=0 that defines animpulse greater than the constant output (b) of the conventional signal.The starting impulse (f) can extend for a time t<1 to urge a fasteropening response (g) of reagent injector 100. It should be appreciatedthat the opening response (g) of the refined control signal of thepresent teachings is quicker (and thus steeper in slope) than theopening response (d) of the conventional control signal. The controlsignal of the present teachings can then be reduced to a lower output(h) at t<1 and held until terminated (i) to zero at t=1. It has beenfound that by using the control signal of the present teachings, reagentinjector 100 is capable of minimizing a delay associated with movingfrom a closed position to an opened position and from the openedposition back to the closed position, and thus is capable of achievingimproved response and metering capability.

The combination of pulse width modulation providing a peak and holdresponse control, and mechanical atomization techniques, is appropriatefor providing small quantities of atomized hydrocarbons with precisetiming. Cooling aspects provided by the present teachings allow injector100 to survive in proximity to hot exhaust gases and preventpre-ignition of the hydrocarbon.

In some embodiments, as depicted in FIG. 2B, reagent injector 100 mayemploy a fluid coupling 160 having a body 162 defining a chamber 164.FIGS. 43 and 44 depict perspective views of fluid coupling 160, whichmay be releasably coupled to injector body upper section 102 a ofinjector body 102 to affect a fluid connection. To this end, chamber 164of body 162 is recessed or concave as a female portion to engage andcouple to a protruding or male portion 166 of injector body uppersection 102 a of injector body 102. With such a construction, a reliableand releasable connection is formed between fluid coupling 160 and theremainder of reagent injector 100. Fluid coupling 160 includes a reagentinlet 168 and a reagent outlet 170 to supply aqueous reagent or urea toa fluid path within reagent injector 100. It should be appreciated thatin some embodiments fluid coupling 160 can comprise a plurality ofseparate lines connectable to a common hub, such as depicted in FIGS.6-8.

According to teachings of the present disclosure, a fluid path isdefined within reagent injector 100 when pintle 118 is in the closedposition to facilitate circulation of fluid through injector 100. Morespecifically, and with reference to FIGS. 18 and 42, the fluid path canextend from reagent inlet 168 to a distribution chamber 171 andsubsequently to reagent outlet 170. In further detail, fluid or reagentmay enter reagent injector 100 at reagent inlet 168 at a firsttemperature, which may be relatively cool. Fluid may then proceed byflowing along a pathway 300 along and against an exterior side of polepiece 122. Pathway 300 may be defined by an exterior surface of polepiece 122 and an inside diameter of chamber 140 of injector body uppersection 102 a. The fluid can then continue in its direction of flow andpass between an exterior surface of pole piece 122 and inside of bobbin144. More specifically, fluid may continue in its direction of flow andpass through at least one slot or a plurality of slots 302 (see FIGS.31-33) formed along the inner diameter of bobbin 144. During this stage,the cool fluid is exposed to an exterior surface area of bobbin 144 andis operable to cool, or absorb a portion of thermal energy from, bobbin144 and associated coil 180, which may transfer heat into bobbin 144.

Alternatively, a separate part, such as a fluid sleeve, may beincorporated within an inside diameter of bobbin 144, or more generally,within an inside diameter of electromagnetic coil 180, to separate theelectromagnetic coil 180 from the fluid path. In utilizing a fluidsleeve, slots 302 may not be necessary, for instance, to permit passageof fluid. With reference to FIGS. 31 and 33, although not particularlydepicted, a fluid sleeve may have a generally smooth exterior adjacentto central bore 146, and a generally smooth interior. A height of such afluid sleeve may be the same or generally the same as a height of bobbin144 depicted in FIG. 33 and disposed within central bore 146 of solenoidcoil bobbin 144. O-rings may be utilized between seals or componentparts, such as between a fluid sleeve within central bore 146 andcentral bore 146.

The presence of cool fluid flowing adjacent bobbin 144 is beneficial tothe operation and longevity of magnetic coil 180 because of theheat-absorbing function of the fluid. The fluid may then proceed inflowing from slots 302 to a lower body passage 304 along an exteriorside or surface of inner lower body 104. More specifically, lower bodypassage 304 may be defined between an exterior side or surface of innerlower body 104 and an interior surface or surface of injector body lowersection 102 b of injector body 102, such as chamber 142 of injector bodylower section 102 b. In some embodiments, lower body passage 304 maycompletely surround part of or an entire length 306 of inner lower body104 to cool inner lower body 104. Moreover, fluid within lower bodypassage 304 can further cool at least a portion of injector body lowersection 102 b of injector body 102. As depicted in FIG. 18, fluid withinlower body passage 304 can be directed to distribution chamber 171 viaone or more distribution passages 308. Fluid within distribution chamber171 can be directed to a swirl chamber 320 when pintle 118 is in anopened or closed position, while cooling orifice plate 108. One or morereturn passages 312 may extend from distribution chamber 171 to centralbore 106 of inner lower body 104 and provide a fluid path for fluid fromdistribution chamber 171 to central bore 106 of inner lower body 104.Fluid within central bore 106 may provide cooling to pintle 118 andinner lower body 104. Upon flowing into central bore 106, fluid may flowfrom along an entire length of central bore 106 such that fluidsurrounds an outside diameter of pintle 118, which may be a solid,non-hollow structure. Fluid may proceed in flowing along a length ofpintle 118 within central bore 106 in a direction away from orificeplate 108 and exhaust stream of exhaust pipe. At an end of central bore106 that is opposite return passage 312, fluid may flow through exitslots or holes, which may be through exit slots or holes 109 in guideplate 107. Guide slot 109 may be solely defined by guide plate 107 andan exterior surface of pintle 118. Upon flowing through one of moreguide slots or holes 109 in guide plate 107, fluid may flow through apassage 316 in pintle head 132, then to central bore 134 of pole piece122, and subsequently to reagent outlet 170 and back to reagent tank 12.Passage 316 may be a through hole in pintle head 132.

From the above discussion, it should be recognized that the flow offluid into and out of injector 100, even when injector 100 is notinjecting fluid into an exhaust stream, provides a cooling effect toreagent injector 100. Moreover, it should be recognized that the flowvelocity from reagent inlet 168 and through pathway 300, slots 302, andlower body passage 304 (generally collectively referred to as thecooling pathway) is less than the flow velocity exiting the reagentinjector 100 through central bore 106, passage 314, passage 316, centralbore 134, and reagent outlet 170 (generally referred to as the heatedpathway) because of the increased volume of the cooling pathway versusthe reduced volume of the heated pathway. Therefore, this reduced flowvelocity of the cooling pathway permits greater fluid presence in termsof fluid volume, longer fluid dwell time, and increased thermalabsorption when the fluid is coolest. Likewise, the increased flowvelocity of the heated pathway permits greater removal of heated fluidfrom reagent injector 100. The overall effect is improved cooling andthermal management of reagent injector 100.

Reagent injector may be in an opened position when pintle 118 is liftedor moved away from orifice plate 108 and fluid is permitted to flowtoward and into an exhaust stream within exhaust pipe 19. Similar to theabove description of fluid flow through injector 100 when reagentinjector 100 is in a closed position, when reagent injector 100 is in anopened position, a free-flowing and unobstructed fluid path extends fromdistribution chamber 171 to a swirl chamber 320 (FIG. 18) via one ormore slots 322 in orifice plate 108 and out of orifice 110 and, forexample, into an exhaust stream within exhaust pipe 19.

Slots 322 may be formed into orifice plate 108, as depicted in FIG. 16.Alternatively, an intermediate plate may have slots 322 formed into it.For example, orifice plate holder 112 depicted in FIGS. 2A-2B may haveslots 322 formed into it. Still yet, slots 322 may be formed into abottom surface of inner lower body 104. Thus, various options exist forforming slots to control reagent flow proximate exit orifice.

It should be recognized that fluid generally flows within swirl chamber320 only when pintle 118 is in the raised and open position and unseatedfrom valve seat 120. This arrangement substantially improves dosage ofreagent from reagent injector 100. That is, a dosage amount inconventional injectors can often vary based on flow velocity, sprayangle, droplet size, and the like. When fluid flow is permitted tofreely flow within a swirl chamber and that flow is varied by parametersettings of the system, such as return line backpressure, velocity, andthe like, the dosage amount of ejected reagent can vary substantially.Therefore, according to the principles of the present teachings, thesedisadvantages can be avoided by, in part, using return passages 312 thatreturn fluid to reagent outlet 170 without the need for the fluid topass through swirl chamber 320. Instead, reagent may pass about aperiphery of swirl chamber, a periphery of slots 322 and raised portionsthat define slots 322.

In other words, in some embodiments, reagent may be delivered to exitorifice 110 via reagent inlet 168. Reagent inlet 168 may be in fluidcommunication with exit orifice 110 and may be externally connected toreagent tank 12 via supply line 9. Reagent may be pumped to reagentinjector 100 at a predetermined pressure set point and into reagentinlet 168 and subsequently to exit orifice 110. The predeterminedpressure set point may vary in response to operating conditions toprovide at least one of increased operating range and varied spraypatterns from exit orifice 110. The pressurized reagent may beaccelerated to a relatively high velocity based on the construction andshape of orifice plate 108. This produces a high velocity flow in theexit orifice 110. When the end of pintle 118 is removed from valve seat120, a portion of the flow of reagent is passed through exit orifice110, where atomization occurs from a combination of centrifugal forceand shearing of the reagent by air as it jets into the exhaust stream.

As an example, approximately 600 milliliters per minute (ml/min), whichconverts to 36 liters per hour (l/hr), of reagent may be circulatedthrough reagent injector 100, which may be greater than an amount ofreagent actually dispensed from exit orifice 110. Although the flow ratemay be varied depending on the specific exhaust treatment application,reagent not dispensed into an exhaust stream via exit orifice 110, exitsreagent injector 100 via reagent outlet 170 and is returned to reagenttank 12 for circulation. Upon removing the end of metering pintle 118from valve seat 120, atomized reagent may be expelled at the rate ofapproximately 1 ml/min (0.06 l/hr) to 600 ml/min (36 l/hr) depending onthe exhaust treatment application and/or the control algorithm used. Thespray characteristics of reagent expelled from exit orifice 110 may bevaried depending on the pressure ratios of the pressure maintained inthe return line 35 to reagent tank 12 from reagent injector 100 and insupply line 24 to reagent injector from delivery module 14. For example,the size of the droplets may be controlled by varying the pressure inthe supply line 24. In addition, the spray characteristics may be variedby interchanging different spray plates or orifice plates. Varying thereagent circulation rate, such as by changing an output pressure bydelivery module 14, can change the level of cooling provided by thereagent, but will no longer have an effect on the droplet size or spraycone angle.

As depicted in FIGS. 2A and 2B, metering pintle 118 may be biased in theclosed position by a biasing member, which may be, for example, in theform of return spring 136 that engages pintle head 132 of pintle 118.Return spring 136 may engage a top surface of pintle head 132 of pintle118. A top surface of pintle head 132 may be a surface of plungeropposite pintle 118. Top surface may be curved or convex.

With particular reference to FIGS. 4, 5 and 43-45, external perspectiveviews of reagent injector 100 depict connection to an exhaust tube 19.In some embodiments, connection of reagent injector 100 to exhaust tube19 can be achieved in such a way as to minimize the disadvantages offorces, such as torque and the like, that can be exerted upon reagentinjector 100. That is, in some embodiments as illustrated in FIGS. 2A,2B, and 9-11, a mounting flange 200 can be coupled to exhaust tube 19via a weld, threaded fastener, or other conventional means. Mountingflange 200 may be formed having a central bore 202 sized to receiveinjector body lower section 102 b of injector body 102 to permit exitorifice 110 to be positioned in a predetermined position within exhausttube 19 to introduce reagent inside of exhaust tube 19 at a desiredorientation. In some embodiments, as depicted in FIGS. 2A, 2B, and 9-11,an insulator 204 may be disposed between mounted flange 200 and injectorbody lower section 102 b of injector body 102 to minimize the transferof thermal energy from exhaust system 18, and more specifically, fromexhaust gases and exhaust tube 19, to reagent injector 100. To furtherresist passage of exhaust gases, an appropriate heat-resistant O-ring203 may be installed at an elbow or shoulder location between insulator204 and mounting flange 200′ as depicted in FIG. 42.

Insulator 204 may be made of a material having thermal properties thatminimize heat transfer, such as Makor or Pressed Mullite. Insulator 204may comprise a tubular section 206 having an outer diameter and/or shapecomplementary to an inner diameter and/or shape of central bore 202 ofmounting flange 200 to permit insulator 204 to be received withinmounting flange 200. Moreover, an outer diameter of tubular section 206may contact an inner diameter of central bore 202 of mounting flange200. Similarly, tubular section 206 may comprise an inner diameterand/or shape complementary to an outer diameter and/or shape of injectorbody lower section 102 b to permit injector body lower section 102 b ofinjector body 102 to be received within insulator 204. Moreover, anouter diameter and/or shape of injector body lower section 102 b maycontact an inner diameter of insulator 204. Insulator 204 may have anoutside diameter that has a series of alternating protrusions andrecessions that limit contact of an outside diameter of tubular section206 to the protruding portions and not the recession portions. With thisconstruction, outside diameter of tubular section 206 has less contactwith an inside diameter of mounting flange 200 and thus, less heattransfer between tubular section 206 and mounting flange 200 will takeplace than if alternating protrusions and recessions were a smoothsurface or part of a threaded contact surface.

Similarly, tubular section 206 may comprise an inner diameter that has aseries of alternating protrusions and recessions that limit contact ofan inside diameter of tubular section 206 with an outer diameter ofinjector body lower section 102 b to the protruding portions and not therecession portions. With this construction, inside diameter of tubularsection 206 has less contact with an outside diameter of injector bodylower section 102 b and thus, less heat transfer between tubular section206 and injector body lower section 102 b will take place than ifalternating protrusions and recessions were a smooth surface or part ofa threaded contact surface.

Insulator 204 has proven to provide substantial thermal insulatingproperties conducive to minimizing heat conduction from exhaust system18 to reagent injector 100. Specifically, by way of non-limitingexample, it has been found that temperatures external to insulator 204can range from 500° C. and higher. However, interior wall temperaturesof bore 202 of insulator 204 do not typically exceed 70-100° C. In someembodiments, insulator 204 is metalized and Nickel brazed to theexternal metal housing or mounting flange 200, 200′. The braze serves toprovide a gas tight seal without resorting to any form of gasket orother sealing device, and to provide retention of the insulator withinthe flange 200. The braze joint has thermal capabilities that are higherthan temperatures that are expected to occur in service with theinjector 100, mounting flange 200 and insulator 204 when installed aspart of an exhaust system, thus ensuring an acceptable margin of safetyfor reliable sealing and attachment.

With continued reference to FIGS. 2A and 2B, injector body lower section102 b of injector body 102 may be fastened to mounting flange 200 via aplurality of fasteners 208, such as cap screws. Fasteners 208 can extendthrough respective apertures 210 formed in a flange ring 212 of injectorbody lower section 102 b and be threadingly engaged with a correspondingaperture 214 formed in a flange ring 216 of mounting flange 200. In someembodiments, a lip 205, which may be circular, of insulator 204 may bepositioned between injector body lower section 102 b and mounting flange200 to reliably retain, or sandwich by contact, insulator 204 therein.Insulator 204 can be used as a pilot for projection welding mountingflange 200 to the exhaust pipe.

In some embodiments, however, as seen in FIGS. 4-8 and 41-42, injectorbody lower section 102 b of injector body 102 may be fastened tomounting flange 200′ via a plurality of clips 220, which incross-section may be C-shaped or oval. Alternatively, clips 220 may beformed in other shapes. For instance, clips 220 may be circular, squareor rectangular in cross-section. Clips 220 may be used to overlap orcover a portion of a peripheral ring section 222 of mounting flange 200′and a peripheral ring section 224 of a retaining plate 226 (FIG. 41-42).As depicted in FIGS. 22-24, retaining plate 226 may be a disc-shapedmember having upturned peripheral ring section 224 and a centralaperture 227 for receiving injector body lower section 102 b of injectorbody 102. Retaining plate 226 may be coupled to injector body lowersection 102 b of injector body 102 via press-fit and brazing or weldingto retain injector body 102 therewith. Each of clips 220 may compriseterminal ends 228 (FIG. 41) that generally face or oppose each other andexert a clamping force on mounting flange 200′ and retaining plate 226to couple injector body 102 to mounting flange 200′. More specifically,with reference continuing with FIGS. 41-42, a first terminal end 228 ofa clip 220 may contact ring section 222 of mounting flange 200′ and asecond terminal end 228 of clip 220 may contact peripheral ring section224 of retaining plate 226 of injector body lower section 102 b ofinjector body 102. Second terminal end 228 of clip 220 may furtherreside within and contact a peripheral concavity 225 of peripheral ringsection 224 of retaining plate 226. Concavity 225 may prevent movementof clip toward and away from a central vertical axis of reagent injector100. Central vertical axis of reagent injector 100 may be coincidentwith a longitudinal axis of pintle 118. By preventing movement of clip220 toward and away from a central vertical axis of reagent injector100, clip 220 remains in its installation position.

To prevent or minimize rotation of injector body lower section 102 brelative to injector body upper section 102 a of injector body 102, andfurther prevent movement of installed clips 220 relative to retainingplate 226 and mounting flange 200′, locating pins 229 (FIGS. 9-11 and41-42) may extend upward from retention holes 223 or slots in mountingflange 200′ and may be received within any one of a number of locatingholes 231, which may be through holes, formed in retaining plate 226(FIGS. 22-23). Locating pins 229 and locating holes 231 engage oneanother and form a connection therebetween that prevents relativerotation of clips 220, retaining plate 226 and mounting flange 200′.Thus, the present disclosure provides an injector and mount interfacethat permits a selection of rotational orientations for desired injectorinstallation, thereby avoiding the need for application specific mountsand components.

With reference including FIGS. 41 and 42, clip 220 may have a notch 235on one of opposing terminal ends 228. For instance, notch 235 may be ona side of reagent injector 100 that is referred to as a top side. A topside of reagent injector 100 may be that side of retaining plate 226that faces away from exhaust tube 19 when reagent injector 100 isinstalled on an exhaust tube 19. Notch 235 may be wider than a diameterof locating pins 229 so that notch 235 of clip 220 may reside over anend of locating pin 220 as depicted in FIG. 42. During an installationof clip 220 to firmly secure retaining plate 226 and peripheral ringsection 222 of mounting flange 200′ together, and prevent relativemovement between retaining plate 226 and peripheral ring section 222,second terminal end 228 of clip 220 with notch 235 may first bepositioned over an end of locating pin 229, which is installed in blindhole of peripheral ring section 222. A portion of clip 220 on eitherside of notch 235 may contact a surface of peripheral ring section 224and clip 220 may also contact locating pin 229. Subsequently, firstterminal end 228 of clip 220 may be pressed around a periphery ofcontact ring section 222 of mounting flange 200′ such that firstterminal end 228 contacts a bevel portion 237 of contact ring section222 before first terminal end 228 of clip 220 comes to rest in groove239 (FIG. 11). Thus, second terminal end 228 of clip 220 is securedwithin concavity 225 of peripheral ring section 224 with locating pin229 residing within notch 235, and first terminal end 228 of clip 220 issecured within groove 239 of peripheral ring section 222. Thus, uponinstallation of clip 220, a longitudinal axis of locating pin 229 maypass through each terminal end 228 of clip 220.

In some embodiments, insulator 204 can be positioned between injectorbody lower section 102 b/retaining plate 226 and mounting flange 200′ toreliably retain insulator 204 therein. It should be appreciated thatclips 220 provide an advantage over traditional torque-based, twistingfasteners in that clips 220 do not exert any twisting or turning force(i.e. torque) on reagent injector 100. Such twisting or turning forceshave been found to damage reagent injectors and/or insulator 204 in someapplications or if improperly installed (e.g. over-torqued) by atechnician. Moreover, clips 220 provide a minimal thermal pathway forthe conduction of heat from mounting flange 200′ to injector body 102,thereby reducing and limiting the thermal load of reagent injector 100that must be dissipated.

In some embodiments, pintle 118, orifice plate holder 112, inner lowerbody 104, pole piece 122, spring pre-loader 138, injector body uppersection 102 a of injector body 102, mounting flange 200, 200′, and/orfluid coupling 160 may be made of type 430C, 440F or similar stainlesssteel, and in some embodiments coated with a coating that retains ureacorrosion resistance and magnetic properties while reducing metalfatigue caused over the life of reagent injector 100. Collar section 126and return spring 136 may be made of type 316 or similar stainless steeland, in some embodiments, coated with a coating that retains ureacorrosion resistance while reducing metal fatigue caused over the lifeof reagent injector 100.

FIGS. 43-45 depicts reagent injector 100, which may employ a heat shield340 to shield injector 100 from radiant heat from exhaust tube 19. Morespecifically, heat shield 340 may be mounted to reagent injector 100using a single aperture through a heat shield surface 342 that isparallel to exhaust tube 19. FIG. 44 depicts a cover 344 that may bepositioned over and around reagent injector 100 to protect reagentinjector from environmental elements such as water, snow, road debris,etc. Moreover, cover 344 may be an insulating cover and insulate reagentinjector 100, inside of cover 344, from the environment located outsideof cover 344. For instance, cover 344 may hold heat generated by reagentinjector 100 within the confines or interior or cover 344, when thetemperature outside of, or surrounding an exterior of, cover 344 islower than the temperature within the confines of cover 344, wherereagent injector 100 is located. Similarly, cover 344 may prevent heatedair located outside of cover 344 from elevating reagent injector 100 toa temperature that hastens solidification or crystallization of reagent,such as urea for example, within reagent injector 100. Cover 344 may bemade of a plastic or metal material, similar to that from which reagentinjector 100 is manufactured. Cover 344 may have a through hole 346through which inlet tube 348 and outlet tube 350 may pass. Electricalwires 352, 354 may also pass through hole 346. Cover 344 may secure ontoheat shield 340 in a press fit, snap fit or other fashion to ensure thatcover 344 remains securely attached to heat shield 340 when reagentinjector 100 with heat shield 340 is in use on an exhaust system, whichmay be employed on a vehicle.

A method of injecting a reagent into a gas stream is also provided inaccordance with the present teachings. FIG. 48 depicts a cross-sectionalview of an example reagent flow path 169 through reagent injector 101.As depicted, liquid reagent, such as urea, enters reagent injector 101at inlet port 167, passes through inlet 168 and flows between an outsidediameter of pole piece 122 and central bore 146 of solenoid coil bobbin144. Because pole piece 122 and solenoid coil bobbin 144 have relativelylarge surface areas within reagent injector 101, liquid reagent mayabsorb heat from these components as reagent flows through reagentinjector 101. Thus, the reagent flowing in accordance with reagent flowpath 169 may become increasingly warmer as the reagent flows throughreagent injector 101. Continuing, reagent proceeds to flow between anouter diameter of collar portion 126 and an inside diameter or centralbore 146 of solenoid coil bobbin 144. Reagent then proceeds to flowthrough lower body passage 304, which is defined between an outsidediameter of inner lower body 104 and an inside diameter of injector bodylower section 102 b. Reagent then reaches a location 172 where innerlower body 104 of reagent injector 101 has been welded to injector bodylower section 102 b of reagent injector 101. At this location, reagentflows from lower body passage 304 and into distribution passages 308 ofinner lower body 104 that allow the reagent to flow into distributionchamber 171, formed between inner lower body 104 and orifice plate 108.If reagent injector 101 is closed, such as when solenoid is not poweredor energized and tip of pintle 118 is seated against and forms a sealwith valve seat 120, which may be a conical surface, of orifice plate108, fluid is prevented from being sprayed into exhaust tube 19 fromexit orifice 110.

With magnetic coil 180 not energized and pintle 118 seated againstorifice plate 108, reagent travels at least part-way around distributionchamber 171 and flows into drillings or holes that connect distributionchamber 171 to central bore 106, which is the central bore of innerlower body 104. This central bore 106 or bore forms a return passage forthe re-circulating reagent that removes heat generated between movingand contacting parts within reagent injector 101. Reagent injector 101may be continuously cooled by circulating reagent even if reagentinjector 101 is not actively injecting fluid into an exhaust stream ofexhaust tube 19. If magnetic coil 180 of solenoid is electricallyenergized causing pintle 118 to be lifted off of and away from orificeplate 108, a portion of reagent will flow through slots 322, which maybe tangential slots or curved slots, and subsequently into swirl chamber320, which is located between tangential slots 322 and exit orifice 110,as depicted in FIG. 16. Only the volume of reagent injected into exhausttube 19 as spray 313 flows through slots 322.

Continuing with FIG. 48, reagent that is directed into central bore 106around pintle 118, flows from pathway 322 around a periphery of slots322 and into passage 312, which directly leads into central bore 106.Upon flowing along a length of central bore 106, reagent may then flowthrough one or more through slots or holes 109 in guide plate 107.Pintle 118 forms a portion of a boundary of each of slots or holes 109when pintle is inserted into center through hole of guide plate 107, asevident from FIGS. 17-18. After reagent passes through guide plate 107,reagent proceeds and passes through one of more through holes 316 inpintle head 132 and proceeds into and through central bore 134, which iswhere spring 136 and spring pre-loader 138 resides. Next, reagent flowsinto reagent outlet 170 and from reagent port 173.

Because only the volume of reagent injected flows through slots 322, asame or similar amount of reagent may be discharged from exit orifice110, even if the volume of return flow through reagent outlet 170 wereto vary by +/−30%. The desensitization of discharged flow vs. returnflow volume permits a simple drilled restrictor orifice to be used forcontrol of return flow and since no critical matching of injectororifice to return flow is needed, it is not necessary to incorporate therestrictor orifice in the injector itself. For water based media,including aqueous Urea, where freezing of the media is possible in coldweather conditions, the restrictor orifice is best positioned at theinlet of the return flow into the tank, since this results in only airbeing drawn through the orifice when the lines are purged of fluid afterengine shutdown. This permits a faster purge cycle, which may alsoachieve the removal of a greater percentage of the fluid in the lines,resulting in a faster thaw cycle on startup.

When reagent injector 101 is undergoing “alternate return flow,” only aportion of reagent exits through orifice plate 108 as spray 313 and intoan exhaust stream of exhaust tube 19. The balance of reagent is returnedto reagent tank 12 and re-circulated. In one example, reagent injector101 may receive 30 liters per hour (l/hr) of reagent through reagentinlet 168 when reagent injector 101 is injecting reagent into exhausttube 19. However, only 5 l/hr may actually exit through exit orifice andinto an exhaust stream in exhaust tube 19. The balance of 25 l/hr may bereturned through reagent injector 101 and exit reagent injector 101 atexit port 165 as return flow.

With reference mainly to FIGS. 18 and 48, in some embodiments, a methodof directing reagent through injector 101 may include receiving areagent from reagent tank 12 at reagent inlet 168 of reagent injector101; directing the reagent to a pole piece passage 324 defined betweenan outside diameter of pole piece 122 and injector body upper section102 a and an inside diameter of electromagnetic bobbin 144; directingthe reagent from the pole piece passage 324 to a collar passage 326defined between an outside diameter of collar 126 of an inner lower body104 and inside diameter of bobbin 144; directing the reagent from thecollar passage 326 to a lower body passage 304 defined between anoutside diameter of inner lower body 104 and an inside diameter ofinjector body lower section 102 b of injector 101; and directing thereagent into a distribution passage 308 defined by inner lower body 104.Distribution passage 308 may fluidly link lower body passage 304 todistribution chamber 171 defined by inner lower body 104 and orificeplate 108. In some embodiments, from distribution chamber 171, themethod may include directing a first partial volume of the reagent toexit orifice 110 in orifice plate 108 and directing a second partialvolume of the reagent to a reagent outlet 170 of injector 101.

In some embodiments, directing a first partial volume of the reagent toexit orifice 110 in orifice plate 108 may include: directing the firstpartial volume of the reagent through plurality of slots 322 in orificeplate 108; moving a pintle 118 and unblocking orifice 110 in orificeplate 108; directing the first partial volume of the reagent through aplurality of slots 322 in orifice plate 108 and through orifice 110; anddirecting the first partial volume of the reagent to a central bore orcentral bore 106 defined by inner lower body 104.

In some embodiments, directing a second partial volume of the reagent toreagent outlet 170 or outlet port 165 may include: directing the secondpartial volume of the reagent through slots or holes 109 (FIG. 17)defined in guide plate 107 through which pintle 118 passes; directingthe second partial volume of the reagent through holes 316 of pintlehead 132, pintle head 132 attaching to and surrounding an end of pintle118; directing the second partial volume of the reagent through aninterior of bobbin 144 of magnetic coil 180; directing the secondpartial volume of the reagent through central bore 134 of pole piece122; directing the second partial volume of the reagent fromdistribution chamber 171 to at least one return passage 312 defined byinner lower body 104. Return passage 312 fluidly links distributionchamber 171 and central bore 134 defined by the inner lower body 104.Directing the second partial volume of the reagent around an outsidediameter of solid pintle 118 residing within central bore 106 defined bythe inner lower body 104.

Alternatively, in some embodiments, a method of directing reagentthrough an injector may entail pumping a reagent from reagent tank 12 toinjector reagent inlet 168; directing the reagent to pole piece passage324 defined between an outside diameter of pole piece 122 and injectorbody upper section 102 a; directing the reagent from the pole piecepassage 324 to a collar passage 326 located between an outside diameterof a collar 126 of inner lower body 104 and an inside diameter of theelectromagnetic coil bobbin 144; directing the reagent from collarpassage 326 to lower body passage 304 located between an outsidediameter of inner lower body 104 and an inside diameter of injector bodylower section 102 b of injector 101; directing the reagent into adistribution passage 308 defined by inner lower body 104, distributionpassage 308 fluidly linking lower body passage 304 and distributionchamber 171 defined by inner lower body 104 and orifice plate 108;dividing the reagent into a first partial volume and a second partialvolume; directing the first partial volume and second partial volume ofthe reagent in the distribution chamber 171; directing the first partialvolume into curved slots 322 defined in the orifice plate; liftingpintle 118 from orifice plate 108; and directing the first partialvolume of the reagent around an orifice 110 in the orifice plate 108.

In some embodiments, a method may further entail directing the firstpartial volume of the reagent from around orifice 110 in orifice plate108 and into exhaust tube 19 (FIG. 44) and directing the second partialvolume of the reagent from reagent outlet 170 and outlet port 165 and toreagent tank 12.

Directing the second partial volume of the reagent to reagent outlet 170may further entail: directing the second partial volume of the reagentto return passage 312 defined in inner lower body 104, return passage312 directing the second partial volume from distribution chamber 171 tocentral bore 106 defined by inner lower body 104; directing the secondpartial volume around an outside diameter of solid pintle 118 residingwithin central bore 106; directing the second partial volume of thereagent through slots or holes 109 of guide plate 107 through whichsolid pintle 118 passes; and directing the second partial volume of thereagent through slots or holes 109 of pintle head 132 to which pintle118 is attached; directing the second partial volume of the reagentthrough inside diameter of the electromagnetic coil bobbin 144;directing the second partial volume of the reagent through centrallongitudinal bore of pole piece 122. Pole piece 122 may be locatedthrough inside diameter of the electromagnetic coil bobbin 144. Apartial volume of the reagent may be directed through a spring 136residing within central longitudinal bore of pole piece 122.

In some embodiments, injector 101 for injecting reagent may employinjector body upper section 102 a, injector body lower section 102 bthat may be secured to injector body upper section 102 a, retainingplate 226 defining circular hole 227 (FIG. 24) such that retaining plate226 may be secured around injector body lower section 102 b via circularhole 227, insulator 204 defining a circular hole or central aperturesuch that insulator 204 may be secured around injector body lowersection 102 b, and mounting flange 200′ defining a circular hole suchthat mounting flange 200′ may be secured around insulator 204. Retainingplate 226 may be secured directly against injector body lower section102 b. Insulator 204 may be secured directly against injector body lowersection 102 b and retaining plate 226. Mounting flange 200′ may besecured directly against insulator 204. Retaining plate 226 may define aplurality of through holes 231 about retaining plate peripheral portion224 or peripheral ring portion 224, and mounting flange 200′ may definea plurality of blind holes 223 about a mounting flange peripheral edge.Pin 229 having a first pin end and a second pin end may be employed suchthat the first pin end resides within one of blind holes 223 of mountingflange 200′ and pin 229 resides completely through one of the pluralityof through holes 231 of the retaining plate 226.

In some embodiments, clip 220 having a first clip end 228 and a secondclip end 228 may be utilized in such a fashion that clip 220 may besecured over retaining plate peripheral portion 224 and mounting flangeperipheral edge or ring section 222. Retaining plate peripheral portion224 may define a peripheral concavity 225 and plurality of through holes231 of retaining plate 226 may be located within peripheral concavity225. Mounting flange peripheral edge may define a groove 239 (FIG. 11).First clip end 228 may reside within groove 239 of mounting flangeperipheral ring section 222 and the second clip end 228 may residewithin peripheral concavity 225 of retaining plate peripheral portion224. Clip 220 may be C-shaped and second clip end 228 may reside on thesecond pin end (FIG. 42). Insulator 204 may define a tubular sectionwith an inside diameter and an outside diameter that each have a seriesof alternating protrusions and recessions (FIG. 11).

In some embodiments, heat shield 340 may be installed on mounting flange200′ using a through hole in the heat shield such that mounting flange200′ may protrude through the through hole of the heat shield 340. Insome embodiments, heat shield 340 may be positioned between an injectorbody upper section 102 a and exhaust pipe 19 (FIG. 44). Cover 344 may bemounted to heat shield 340 such that cover 344 surrounds injector bodyupper section 102 a, injector body lower section 102 b, and mountingflange 200′.

In some embodiments, an injector for injecting reagent may employcylindrical pole piece 122 defining a pole piece first end and a polepiece second end (FIG. 21). Pole piece 122 may have a hollow interiorfrom the pole piece first end to the pole piece second end. Springpre-loader 138 may be located within hollow central bore 134 and againsta portion of the first end. Spring 136 may be located within centralbore 134 and abut spring pre-loader 138. Electromagnetic coil 180 may besecured around bobbin 144 and electromagnetic coil 180 may itselfsurround an outside diameter of the cylindrical pole piece 122. In someembodiments, cylindrical pole piece 122, spring pre-loader 138, spring136 and electromagnetic coil 180 reside only within a cavity or chamberof injector body upper section 102 a.

A cylindrical inner lower body 104 may reside within a injector bodylower section 102 b and define a longitudinal central bore 106. An innerlower body first end may define a first end first bore with a diameterlarger than a diameter of the longitudinal central bore. The inner lowerbody first end may also define a first end second bore with a diameterlarger than the longitudinal central bore and larger than the first endfirst bore. An inner lower body second end may define a second end borewith a diameter larger than the longitudinal central bore. Injector 101may further employ solid pintle 118 residing within longitudinal centralbore 106. Guide plate 107 may be attached to intermediate portion ofpintle 118. Guide plate 107 may reside within the first end first bore.Pintle head 132 may surround an end of the pintle 118, or part of theend of pintle 118. Pintle head 132 may reside within the first endsecond bore and orifice plate 108 may reside within the second end bore.Cylindrical pole piece 122, spring pre-loader 138, spring 136,electromagnetic coil 180, cylindrical inner lower body 104, pintle 118,guide plate 107, pintle head 132 and orifice plate 108 may be part of asingle cartridge for easy insertion into injector body upper section 102a, such as into a central chamber.

Guide plate 107 may define one or more through slots or holes 109 forpassage of fluid. Alternatively, guide plate 107 and pintle 118 togethermay define one or more through slots or holes 109 therebetween forpassage of fluid. Pintle head 132 may define at least one through hole316 for passage of fluid. Orifice plate 108 and inner lower body secondend may define a distribution chamber 171 therebetween. Orifice plate108 may define a plurality of grooves 322 for passage of fluid to exitorifice 110 for exit from injector 101. Interior surface of injectorbody lower section 102 b and inner lower body exterior surface maydefine a fluid passage 304. Inner lower body 104 may define adistribution passage 308 fluidly linked to passage 304 defined by aninterior surface of the injector body lower section and an exteriorsurface of the inner lower body (FIGS. 18 and 48). Inner lower body 104may define a return passage 312 that fluidly links inner lower bodycentral bore 106 and distribution chamber 171 defined by orifice plate108 and inner lower body second end. Solid pintle 118 may reside withinlongitudinal central bore 106 for passage of fluid around an exterior ofsolid pintle 118 and through longitudinal central bore 106.

The present disclosure offers many advantages. Injectors 100, 101 offera reduction in physical size over previous injectors, which reducesmaterial cost, improves packaging and also reduces absorbed heat from ahot exhaust system. Injectors 100, 101 may eliminate threaded joints andinstead utilize press fits, which are self-fixturing, that aresubsequently welded. Injectors 100, 101 may eliminate O-rings incomparison to previous injectors, especially in the injector body lowersection and inner lower body where exposure to relatively hightemperatures is likely to occur. Injectors 100, 101 improve the responsetime (open and close time) of the injector (lifting up and down ofpintle 118, thus uncovering and covering respectively, orifice 110 oforifice plate 108) to permit higher turn down ratios to be achieved,thus requiring a smaller number of discreet injectors to cover aparticular range of dosing requirements, which reduces inventory andimproves efficiency of scale. Injectors 100, 101 exhibit an improvementin dosing accuracy and repeatability, including a reduction insensitivity to battery voltage, return flow rate and injector bodytemperature variations. Injectors 100, 101 exhibit a relocation of fluidconnectors (e.g. location of fluid inlet 168 and fluid outlet 170) toinjector body upper section 102 a, thereby improving resistance toradiated heat and heat convection from hot exhaust system 18, forexample, in the event that fluid inlet 168 and fluid outlet 170 are madeof a plastic material or other material that is heat-sensitive.Injectors 100, 101 route the coolest fluid, which may be from inlet port167, through the most heat sensitive component, such as solenoid coil180, on the fluid's flow to what may be the hottest part of injectors100, 101, such as orifice plate 108, from which heat is extracted,thereby maintaining injector serviceability despite exhaust gastemperatures of about 800° C. Injector surfaces have relatively largeexposed external surface areas while keeping all enclosed volumes lowfor effective heat transfer to internal fluid.

All injector return flow passages, such as those fluid passages throughwhich fluid flows after passing through distribution chamber 171, bycomparison, may have a lower internal surface area than flow passagesleading up to distribution chamber 171 to reduce heat transfer of thewarmed fluid to sensitive components as it makes its way to outlet port167. Orifice plate 108 may be made from carbide due to carbide'scompatibility with brazing processes, high hardness capabilities andmaterial toughness. Carbide further has the advantage of being moldable,thus relatively small, intricate components can be mass produced in acost effective manner with virtually no finishing operations compared tocomponents machined from heat treatable steels. Injectors 100, 101utilize a mount against exhaust system 18 that utilizes materialsimpervious to the temperatures expected in service on a diesel exhaustafter treatment system. Moreover, the system does not rely oncarbon-based gaskets. Insulator 204 in an injector mount may be attachedand sealed to the “hot” side of any mount joint by a means resistant totemperatures approaching 700° C., such as a nickel braze. The cool sideof any mount joint may be sealed by a conventional Viton O-ring toprovide reliable low leak performance. Insulator 204 should have lowporosity to permit an O-ring to seal effectively to insulator 204,regardless of which side or surface O-ring is disposed. For instance,O-ring 203 may be installed as depicted in FIG. 42, such as betweeninsulator 204 and injector body, such as injector body lower section 102b, or installed between mounting flange 200′ and insulator 204, orbetween retaining plate 226 and insulator 204, such as against anunderside of retaining plate 226. Injectors 100, 101 also provide anadvantage in that when pintle 118 is lifted and uncovers orifice 110,only the fluid that exits injectors 100, 101 through orifice 110, iswhat passes through slots 322, and during periods of non-injection,bypass return flow, which passes around an not through slots 322, isdirected back through injectors 100, 101 to cool injector components.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the invention. Individual elements or features ofa particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the invention, and all such modificationsare intended to be included within the scope of the invention.

It should now be appreciated that the present invention providesadvantageous methods and apparatus for injecting an aqueous ureasolution into the exhaust stream of a diesel engine in order to reduceNOx emissions. Example embodiments are provided so that this disclosurewill be thorough, and will fully convey the scope to those who areskilled in the art. Numerous specific details are set forth such asexamples of specific components, devices, and methods, to provide athorough understanding of embodiments of the present disclosure. It willbe apparent to those skilled in the art that specific details need notbe employed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

1. A method of directing reagent through an injector, the methodcomprising: receiving a reagent at a reagent inlet; directing thereagent to a pole piece passage defined between an outside diameter of apole piece and an inside diameter of a bobbin; directing the reagentfrom the pole piece passage to a collar passage defined between anoutside diameter of a collar of an inner lower body and the insidediameter of the bobbin; directing the reagent from the collar passage toa lower body passage defined between an outside diameter of the innerlower body and an inside diameter of a lower section of the injector;directing the reagent into a distribution passage defined by the innerlower body, the distribution passage fluidly linking the lower bodypassage to a distribution chamber defined by the inner lower body and anorifice plate; directing a first partial volume of the reagent to anorifice in the orifice plate; and directing a second partial volume ofthe reagent to a reagent outlet.
 2. The method of directing reagentthrough an atomizing injector according to claim 1, wherein directing afirst partial volume of the reagent to an orifice in the orifice platefurther comprises: directing the first partial volume of the reagentthrough a plurality of slots in the orifice plate.
 3. The method ofdirecting reagent through an injector according to claim 1, whereindirecting a first partial volume of the reagent to an orifice in theorifice plate further comprises: moving a pintle and unblocking theorifice in the orifice plate; and directing the first partial volume ofthe reagent through a plurality of slots in the orifice plate andthrough the orifice.
 4. The method of directing reagent through anatomizing injector according to claim 1, wherein directing a firstpartial volume of the reagent to a reagent outlet further comprises:directing the first partial volume of the reagent to a central boredefined by the inner lower body.
 5. The method of directing reagentthrough an atomizing injector according to claim 1, wherein directing asecond partial volume of the reagent to a reagent outlet furthercomprises: directing the second partial volume of the reagent throughholes defined in a guide plate through which a pintle passes.
 6. Themethod of directing reagent through an atomizing injector according toclaim 1, wherein directing a second partial volume of the reagent to areagent outlet further comprises: directing the second partial volume ofthe reagent through holes of a pintle head, the pintle head attaching toand surrounding an end of the pintle.
 7. The method of directing reagentthrough an atomizing injector according to claim 1, wherein directing asecond partial volume of the reagent to a reagent outlet furthercomprises: directing the second partial volume of the reagent through aninterior of a bobbin of a magnetic coil.
 8. The method of directingreagent through an atomizing injector according to claim 1, whereindirecting a second partial volume of the reagent to a reagent outletfurther comprises: directing the second partial volume of the reagentthrough a central bore of a pole piece.
 9. The method of directingreagent through an atomizing injector according to claim 1, whereindirecting a second partial volume of the reagent to a reagent outletfurther comprises: directing the second partial volume of the reagentfrom the distribution chamber to at least one return passage defined bythe inner lower body, wherein the return passage fluidly links thedistribution chamber and a central bore defined by the inner lower body.10. The method of directing reagent through an atomizing injectoraccording to claim 1, wherein directing a second partial volume of thereagent to a reagent outlet further comprises: directing the secondpartial volume of the reagent around an outside diameter of a solidpintle residing within a central bore defined by the inner lower body.11. A method of directing reagent through an injector, the methodcomprising: pumping a reagent from a reagent tank to an injector reagentinlet; directing the reagent to a pole piece passage defined between anoutside diameter of a pole piece and an inside diameter of an uppersection of the injector; directing the reagent from the pole piecepassage to a bobbin passage located between an outside diameter of thepole piece and an inside diameter of the electromagnetic coil bobbin;directing the reagent from the pole piece passage to a collar passagelocated between an outside diameter of a collar of an inner lower bodyand an inside diameter of the electromagnetic coil bobbin; directing thereagent from the collar passage to a lower body passage located betweenan outside diameter of the inner lower body and an inside diameter of alower section of the injector; directing the reagent into a distributionpassage defined by the inner lower body, the distribution passagefluidly linking the lower body passage and a distribution chamberdefined by the inner lower body and an orifice plate; dividing thereagent into a first partial volume and a second partial volume;directing the first partial volume and second partial volume of thereagent into the distribution chamber; directing the first partialvolume into curved slots defined in the orifice plate; lifting a pintlefrom the orifice plate; and directing the first partial volume of thereagent around an orifice in the orifice plate.
 12. The method ofdirecting reagent through an injector according to claim 11, the methodfurther comprising: directing the first partial volume of the reagentfrom around the orifice in the orifice plate and into an exhaust tube.13. The method of directing reagent through an injector according toclaim 11, the method further comprising: directing the second partialvolume of the reagent to a reagent outlet.
 14. The method of directingreagent through an injector according to claim 13, the method furthercomprising: directing the second partial volume of the reagent from thereagent outlet and to the reagent tank.
 15. The method of directingreagent through an injector according to claim 13, wherein directing asecond partial volume of the reagent to a reagent outlet furthercomprises: directing the second partial volume of the reagent to areturn passage defined in the inner lower body, the return passagedirecting the second partial volume from the distribution chamber to acentral bore defined by the inner lower body.
 16. The method ofdirecting reagent through an atomizing injector according to claim 13,wherein directing the second partial volume of the reagent to a reagentoutlet further comprises: directing the second partial volume around anoutside diameter of a solid pintle residing within the central bore. 17.The method of directing reagent through an atomizing injector accordingto claim 13, wherein directing the second partial volume of the reagentto a reagent outlet further comprises: directing the second partialvolume of the reagent through holes of a guide plate through which thesolid pintle passes; and directing the second partial volume of thereagent through holes of a pintle head to which a pintle is attached.18. The method of directing reagent through an atomizing injectoraccording to claim 13, wherein directing a second partial volume of thereagent to a reagent outlet further comprises: directing the secondpartial volume of the reagent through the inside diameter of theelectromagnetic coil bobbin.
 19. The method of directing reagent throughan atomizing injector according to claim 13, wherein directing a secondpartial volume of the reagent to a reagent outlet further comprises:directing the second partial volume of the reagent through a centralbore of a pole piece, wherein the pole piece is located through insidediameter of the electromagnetic coil bobbin.
 20. The method of directingreagent through an atomizing injector according to claim 13, whereindirecting a second partial volume of the reagent to a reagent outletfurther comprises: directing a partial volume of the reagent through aspring residing within a central bore of a pole piece.
 21. An injectorfor injecting reagent, the injector comprising: an upper injector body;a lower injector body that is secured to the upper injector body; aretaining plate defining a circular hole, the retaining plate securedaround the lower injector body via the circular hole; an insulatordefining a circular hole, the insulator secured around the lowerinjector body; and a mounting flange defining a circular hole, themounting flange secured around the insulator.
 22. The injector of claim21, wherein the retaining plate is secured directly against the lowerinjector body.
 23. The injector of claim 21, wherein the insulator issecured directly against the lower injector body and the retainingplate.
 24. The injector of claim 21, wherein the mounting flange issecured directly against the insulator.
 25. The injector of claim 21,wherein the retaining plate defines a plurality of through holes about aretaining plate peripheral edge and the mounting flange defines aplurality of blind holes about a mounting flange peripheral edge. 26.The injector of claim 25, further comprising: a pin having a first pinend and a second pin end, wherein the first pin end resides within oneof the blind holes of the mounting flange and the pin resides completelythrough one of the plurality of through holes of the retaining plate.27. The injector of claim 26, further comprising: a clip having a firstclip end and a second clip end, the clip secured over the retainingplate peripheral edge and the mounting flange peripheral edge.
 28. Theinjector of claim 27, wherein the retaining plate peripheral edgedefines a peripheral concavity and the plurality of through holes of theretaining plate are located within the peripheral concavity.
 29. Theinjector of claim 28, wherein the mounting flange peripheral edgedefines a groove.
 30. The injector of claim 29, wherein the first clipend resides within the groove of the mounting flange peripheral edge andthe second clip end resides within the peripheral concavity of theretaining plate peripheral edge.
 31. The injector of claim 21, whereinthe clip is a C-shaped and the second clip end resides on the second pinend.
 32. The injector of claim 31, wherein the insulator defines atubular section with an inside diameter and an outside diameter thateach have a series of alternating protrusions and recessions.
 33. Theinjector of claim 21, further comprising: a heat shield defining athrough hole, the mounting flange protruding through the through hole ofthe heat shield.
 34. The injector of claim 33, wherein the heat shieldis positioned between the injector upper body and an exhaust pipe. 35.The injector of claim 34, further comprising: a cover mounted to theheat shield, wherein the cover surrounds the upper injector body, thelower injector body, and the mounting flange.
 36. An injector forinjecting reagent, the injector comprising: a cylindrical pole piecedefining a pole piece first end, a pole piece second end and a hollowinterior from the pole piece first end to the pole piece second end; aspring pre-loader located within the hollow interior and against aportion of the first end; a spring located within the hollow interior,the spring the abutting the spring pre-loader; and an electromagneticcoil secured around a bobbin, the electromagnetic coil surrounding anoutside diameter of the cylindrical pole piece, wherein the cylindricalpole piece, spring pre-loader, spring and electromagnetic coil resideonly within the upper injector body.
 37. The injector of claim 36,further comprising: a cylindrical inner lower body defining alongitudinal central bore; an inner lower body first end defining afirst end first bore with a diameter larger than a diameter of thelongitudinal central bore, the inner lower body first end also defininga first end second bore with a diameter larger than the longitudinalcentral bore and larger than the first end first bore; and an innerlower body second end defining a second end bore with a diameter largerthan the longitudinal central bore.
 38. The injector of claim 37,further comprising: a solid pintle residing within the longitudinalcentral bore; a guide plate attached to an intermediate portion of thepintle, the guide plate residing within the first end first bore; apintle head surrounding an end of the pintle, the pintle head residingwithin the first end second bore; and an orifice plate residing withinthe second end bore.
 39. The injector of claim 38, wherein thecylindrical pole piece, spring pre-loader, spring, electromagnetic coil,cylindrical inner lower body, pintle, guide plate, pintle head andorifice plate are part of a single cartridge.
 40. The injector of claim39, further comprising: an injector body upper section defining achamber, wherein the single cartridge inserts into and resides withinthe chamber.
 41. The injector of claim 38, wherein the guide platedefines at least one through hole for passage of fluid.
 42. The injectorof claim 38, wherein the guide plate and the pintle define at least onethrough hole therebetween for passage of fluid.
 43. The injector ofclaim 38, wherein the pintle head defines at least one through hole forpassage of fluid.
 44. The injector of claim 38, wherein the orificeplate and the inner lower body second end define a chamber therebetween.45. The injector of claim 38, wherein the orifice plate defines aplurality of grooves for passage of fluid.
 46. The injector of claim 42,further comprising: an injector body lower section, wherein an interiorsurface of the injector body lower section and an inner lower bodyexterior surface define a pathway.
 47. The injector of claim 46, whereinthe inner lower body defines a distribution passage fluidly linked tothe pathway defined by an interior surface of the injector body lowersection and an exterior surface of the inner lower body.
 48. Theinjector of claim 44, wherein the inner lower body defines a returnpassage that fluidly links the inner lower body central bore and thechamber defined by the orifice plate and the inner lower body secondend.
 49. The injector of claim 48, wherein the solid pintle resideswithin the longitudinal central bore for passage of fluid around thesolid pintle.
 50. The method of directing reagent through an atomizinginjector according to claim 1, wherein directing a first partial volumeof the reagent to an orifice in the orifice plate further comprises:directing the first partial volume of the reagent through a plurality ofslots defined in an orifice plate holder.
 51. The method of directingreagent through an atomizing injector according to claim 50, wherein theorifice plate holder and orifice plate are physically separate pieces.52. The method of directing reagent through an atomizing injectoraccording to claim 1, wherein directing a second partial volume of thereagent to a reagent outlet further comprises: directing the secondpartial volume of the reagent from the distribution chamber to at leastone return passage defined by an orifice plate holder, wherein thereturn passage fluidly links the distribution chamber and a central boredefined by the inner lower body.